The present invention relates to gate drivers for depletion mode devices, e.g., in buck converters and more particularly to generating gate drive signals for providing negative voltage offset for turning off depletion mode devices.
When gate to source voltage of a depletion mode device, such as a GaN device, is zero, the device is in ON state. To turn OFF the depletion mode device, a negative voltage needs to be applied on its gate, referenced to source. Gate drivers used for enhancement mode power MOSFETs can not work with the depletion mode devices directly. Therefore, new schemes have to be developed to drive depletion mode devices.
What is needed are new driving schemes for use with gate drivers for depletion mode devices, and in particular, in DC/DC Buck converter circuits.